Litime lifepo4 100Ah Solar Charge maximum Amperage without damage

[andymac506]

I have two LITime lifepo4 12.8 100Ah batteries that I have connected to two 100watt renogy solar panels with a 20A Mppt Rover charge controller.
My question is if I upgrade to 4x 100 watt panels and a new 40A MPPT charge controller will the charge amperage be too much for the batteries?
The Litime booklet states the charge current should be 20A, will using a 40A MPPT controller potentially damage or take life expectency away from my batteries.

im using these in a RV and not really powering much besides a small tv at night which only consumes 35 watts and the obvious water pump and the odd light just a fyi.

Also I apologize if this is a question already covered but I searched and could not find an answer anywhere.

 

[BentleyJ]

A normal charging rate for LiFePO4 batteries is 0.2C which is 20A per 100Ah battery. You have 2 batteries so 40A of charging current would be the recommended amount.

The 400W rating of the panels is a STC standardized rating under ideal test conditions. Typical real output is lower. You probably do not need a 40A charger since 400W when converted to 14V for charging is only going to be a maximum of about 25A after considering losses.

 

[andymac506]

thanks for the response so fast, so I was thinking the 40A MPPT incase I wanted to added maybe one or two more panels later on down the road just to avoid have to buy a third charge controller. What would the best wiring be for 4x 100 watt panels to charge those batteries (series or parallel)? keep in mind I do have a air con on the roof that would put out some shade.
Im trying to learn all this stuff but its a lot to take in and if im not mistaken, series wiring can't have any shade on panels? does this cause all panels to basically stop working? or does it just dim down the output of the panels greatly?

 

[BentleyJ]

According to the Renogy datasheets their 100W panels have a Voc of 24.3V so if you put all 4 panels in series it would exceed the maximum charge controller 95V limit. Especially in cold weather. Your only choice is 2S2P.